1. Field of the Invention
The present invention relates to an image forming system, such as a copier, a printer, a facsimile, etc., and in particular, to a developing apparatus and a process cartridge implemented in an image forming system and so on.
2. Discussion of the Background Art
Various ideas have been proposed to suppress drop of toner from a development casing in the developing apparatus of an image forming system. As one attempt among them, the Japanese Patent Application Laid Open No. 2005-201943 proposes a technology to suppress toner drop from a region between a developer thickness adjusting member located above an opening partially formed on a development casing and a developing region, in which the developer carrier opposes the photo-conductive member in a developing apparatus. The developing apparatus includes a developer carrier vertically moves in the opening while opposing a photo-conductive member through the opening.
According to such an attempt, since toner drop from the development casing in the vicinity of the opening on the upstream side in the developer carrier movement direction (i.e., above the opening) is suppressed, an interrupted image produced due to the toner drop in the developing region can likely be suppressed. Further, a stain of an image caused by adhesion of toner onto a transfer sheet fed below the developing region, and a problem of a sensor caused by adhesion of toner onto an intermediate transfer sheet, as well as a stain in a machine or the like can be suppressed.
However, such a conventional developing apparatus still needs some improvements, in particular, when two-component developer is utilized.